File:Image from page 80 of "Practical methods of organic chemistry" (1901) (14768464341).jpg

Identifier: practicalmethods00gatt Title: Practical methods of organic chemistry Year: 1901 (1900s) Authors: Gattemann, Ludwig. [from old catalog] Subjects: Publisher: [n.p.] Contributing Library: The Library of Congress Digitizing Sponsor: The Library of Congress

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Text Appearing Before Image: ed protecting case of ironclosed at one end, in which the glass tube is so placed that thecapillary portion is at the open end. In transferring the glasstube to the iron casing the latter is not held vertically, but isslightly inclined from the horizontal, so that the glass tube may HEATING UNDER PRESSURE 61 not be broken by suddenly striking the bottom. The iron caseis pushed into the furnace open end first, so that in case cf anexplosion the fragments of glass are not thrown out of the for-ward end but from the rear of the furnace, directed toward a wall.A fragment cage renders the flying pieces of glass harmless.After the tube is in position the front opening is closed by a drop-slide. The tubes are not heated at once up to the desiredtemperature, but are warmed gradually. If it is desired toheat a furnace similar to the one represented to a low tempera-ture, the gas tubes are raised and small flames used, rather thana lowering of the gas-tube and the corresponding increase in size

Text Appearing After Image: Fig. 45- of flame. The danger of the bursting of the glass tubes maybe diminished in many cases, particularly in those in which avery high pressure is developed, by interrupting the heating aftera certain length of time, opening the capillary after the tube hascompletely cooled, and allowing the gases which have been gen-erated to escape. The tube is then resealed and heated again. If tubes are to be heated not higher than ioo°, the convenientso-called water-bath cannon is used, in which the case enclos-ing the tube is heated by steam at ordinary pressure; in this caseoverheating is impossible. Opening the Tubes. — Sealed tubes must not be opened untilafter they are completely cold. The protecting case of iron, con-taining the tube, is removed from the furnace and held in a slightly 62 GENERAL PART inclined position, the end of the capillary being higher than therear end. By means of a slight jerk the capillary end of the glasstube is caused to project from the iron case. The extre

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